Fair enough. I was thinking about the typical single-use zoning in the US, where single-family home zone is different from row-house zone. I agree that we'd be better off with urban zones not making a distinction. However, I'll gladly take small changes in that direction (allowing duplexes and ADUs) over no progress at all.

Setbacks are required in cities, otherwise many buildings wouldn't receive any natural light at ground level. Two- and three-story buildings don't really need them, the sidewalk is enough.

Also setbacks help slow the spread of fire if one building catches on fire.

That brings to mind one crank concept for bureaucratic reform of explicitly embedded purpose formatted laws to slow the spread of fire and perhaps "generally accepted solutions" added after testing to skip design approval.

Thus you could use setbacks as firebreaks, firewalls, or say something exotic like aerogel barricades.

Yeah, that's what we did buying in the burbs. Now they want to change all the zoning.